Generally, a video tape cassette has a housing made up of upper and lower body portions, and a supply reel and a take up reel are provided within the housing. Video tape is wound on the reels and runs under the protection of both reels. In order to improve the stability of the wheels when rotating, they are urged toward the lower part of the cassette housing by a support spring installed on the inner surface of the upper portion of the cassette housing.
In forming such a support spring, a thin metallic plate made of stainless steel has been used in the past. As illustrated in FIGS. 8A and 8B, bending parts 21, 21' are formed in the thin metallic plate to provide an elastic urging force and elastic pieces 22, 22' may be formed on the bending parts 21, 21'.
In the case the design of FIG. 8A, in forming the aforesaid support spring 20, the elasticity to be obtained therefrom is dependent only on the bending parts 21, 21' and thus the design tends to be too stiff. In the case of the design of FIG. 8B it has a problem in that while elasticity is improved by partially cutting off the bending parts 21, 21', it is difficult to maintain a given elasticity effectively for a long time.
The aforesaid two support springs also increase cassette production costs by using relatively expensive stainless steel and by increasing the manufacturing processing required by adding a pressing step to form the bending parts 21, 21'.
Recognizing that such metallic support springs are uneconomical and impractical, the present invention aims to reduce the manufacturing processes and production costs by providing a support spring made with relatively inexpensive synthetic resin and to improve its function by providing good elasticity.